Clegg, John <br/><br/>
The world of a pond  [slide] / 
by John Clegg 
 - [S.l.], :  Focal Point Audio Visual Ltd.,  1981 
 - 50 slides :  col., ;  5 X 5 cm. +  1 note 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Freshwater ecology<br/>Ecology